Five years ago Mike Bart-lett burst onto the theatrical landscape with small, powerful plays that packed huge emotional punches. The first revealed the emotional wreckage caused by an estranged couples' relationship with their offspring (My Child). Another (Cock) delved into the dilemma of a man who has to choose which of two potential life partners - one male, the other female - he should build a future with.

Now Bartlett is one of a handful of must-see playwrights. His first-night audiences are populated by everyone who is anyone in the theatre. And as his reputation has grown bigger, so has the scale of his plays.

He now writes large state-of-the-nation dramas about the environment, or how we blunder into war or, as is the case here, about how the baby boomers of the 1960s - the generation that got high, broke free of deference and whose manifesto for the future consisted of peace and love - how they have selfishly grasped the nation's wealth for themselves, benefited from property price rises and continue to live off the fat of the land and chunky pensions at the expense of future generations, including their own children.

But unlike Bartlett's early work these later plays do not feel as if they have emerged from the playwright's soul. Rather, they feel the result of huge talent whose current objective is to keep hold of the early success it so richly deserved.

This latest offering is split into three entertaining acts. Kenneth and Sandra are free-spirited students when we first meet them. The second and third acts see the couple as stressed, middle-aged parents who unburden their malfunctioning relationship onto their young children, and then as divorced sixtysomethings living life as they always have - selfishly.

There is no doubt that Bartlett is on to something. While much of our ageing population rattle around in big houses, their children long departed, most young people have little hope of affording the tiniest home.

But it feels as if Bartlett has chosen to write about this big issue because it is topical and relevant. He is interested in the idea, not so much the characters. When confronted by their grown-up daughter Rosie (Claire Foy), Kenneth and Sandra declare that they have worked hard for the wealth. And Sandra paints herself as a kind of pioneer for women in the workplace. But we are never told what they actually do, or did.

Still, the dialogue is as sharp and as funny as ever, and James Grieve's production is very well acted, even if Ben Miles and Victoria Hamilton make much more convincing forty- and sixtysomethings than they do 19-year-olds. But Bartlett needs to start writing from the heart again. (Tel: 020 7565 5000)